|
这里是在简体中文雅虎网站中输入“万有引力”得到的万有引力定律：定律中有“任何”等绝对化的字。
万有引力定律 dvvv万有引力定律 （law of gravitation）物体间相互作用的一条定律，1687年为牛顿所现。任何物体之间都有相互吸引力，这个力的大小与各个物体的质量成正比例，而与它们之间的距离的平方成反比。如果用m1、m2表示两个物体的质量，r表示它们间的距离，则物体间相互吸引力为F=（Gm1m2）/r2，G称为万有引力常数。万有引力定律是牛顿在1687年出版的《自然哲学的数学原理》一书中首先提出的。牛顿利用万有引力定律不仅说明了行星运动规律，而且还指出木星、土星的卫星围绕行星也有同样的运动规律。他认为月球除了受到地球的引力外，还受到太阳的引力，从而解释了月球运动中早已发现的二均差、出差等。另外，他还解释了慧星的运动轨道和地球上的潮汐现象。根据万有引力定律成功地预言并发现了海王星。万有引力定律出现后，才正式把研究天体的运动建立在力学理论的基础上，从而创立了天体力学。 这里是skybrother先生对英文牛顿万有引力定律的解释 ：他认为在英文原文中，牛顿没有用“任何”等绝对化的字。 《如果你对"引力", 这个词的定义是包括"重力引力和电磁力, 我没话好说, 每个人对每个词的定义都是不同的. 但我不同意的是,你没有证明重力引力和电磁力的统一. 所谓统一理论, 在某个特殊情况下, 这两个力是相同的. 现在, 重力引力和电磁力作用对象和方式都是不同的, 你倒怎么个统一? 在你的几篇文章中你都只是咬文嚼字. 牛顿说的引力本来就是重力引力,只不过翻译时为了简便就译成"引力",他所有的公式都是只和重力引力有关, 没有包括电磁力, 也没有反对电磁力. 在英语中"万有引力"是"GRAVITY", 单单的引力是"ATRACTIVE FORCE". 也就是说牛顿在定义引力定律时指的只是重力引力. 你只是改变一个词的定义也能叫科学成就?》 这里是在英文雅虎网站中输入law of gravitation得到的英文牛顿万有引力定律原文， 在英语中，any是“任何”的意思。skybrother先生：你不想说点什么吗？ 刘武青 2001/02/03 Next: Problems Up: Circular Motion and the Previous: Centripetal Acceleration Newton's Law of Gravitation Idea: Newton's Universal Law of Gravitation states that any two objects exert a gravitational force of attraction on each other. The direction of the force is along the line joing the objects (See Fig.(7.3)). The magnitude of the force is proportional to the product of the gravitational masses of the objects, and inversely proportional to the square of the distance between them. For the two objects in Figure 7.3: Figure 7.3: Gravitational Force Between Two Masses m1 exerts a force on m2 . m2 exerts a force on m1 . By Newton's third law: = - . The magnitude of the gravitational force is: F12 = G. (22) G is Newton's constant: G = 6.67 x 10- 11 N m 2 /kg 2. (23) Note: The inertial mass of an object determines the amount of force needed to produce a given acceleration of that object. The gravitational mass determines the force of gravitational attraction between two bodies. In Newtonian mechanics, these two masses have no obvious connection with each other. Nonetheless, it was observed empirically that they are numerically equal. This remarkable fact was known for centuries, but remained unexplained until Einstein's General Theory of relativity. Newton's gravitational constant is extremely small when expressed in terms of laboratory sized objects: the gravitational force between two 1 kg objects separated by 1 m is only 6.67 x 10- 11 Newtons. For an object of mass m near the Earth's surface: Fgrav = - Gm = - mg (24) where ME = 5.98 x 1024 kg is the mass of the Earth and RE = 6.38 x 106 m is the radius of the earth and g G = 9.8 m/s 2 (25) in agreement with the expression in Chapter 3. Definition: Gravitional Potential Energy Due to the gravitational force of attraction, any two objects with masses m1 and m2 located a distance r apart have the ability to do work. Hence they have potential energy. The gravitational potential energy of such objects is: PE grav = - G. (26) Note: Recall that only differences in potential energy are physically relevant. In the above, the zero of gravitational potential energy has been arbitrarily chosen to be zero at r = . i.e. when the objects are infinitely far apart. The negative sign is a consequence of the attractive nature of the gravitational force. When the objects are far apart, the gravitational force naturally moves them closer, decreasing their potential energy (i.e. making it more negative). Gravitational potential energy near Earth's surface: For an object of mass m a distance h above the earth's surface: PE grav = - G. If h < < RE we can approximate: so that: PEgrav - G = - G + mh = constant + mgh. (27) This agrees with the expression used in Chapter 5. -------------------------------------------------------------------------------- Next: Problems Up: Circular Motion and the Previous: Centripetal Acceleration www-admin@theory.uwinnipeg.ca 10/9/1997 ----------------------------------------------------------------- Help - Personalize Search Result Found about 16900 web pages for law of gravitation www. Categories Web Sites Web Pages Related News Events Search Books! * LAW OF GRAVITATION * Search Books * Search DVD/Video Web Page Matches (1 - 20 of about 16900) Sir Isaac Newton: The Universal Law of Gravitation Sir Isaac Newton: The Universal Law of Gravitation. There is a popular story that Newton ... http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html [More results from csep10.phys.utk.edu] Newton's Law of Gravitation ... Newton's Law of Gravitation. Idea: Newton's Universal Law of Gravitation states that any two ... http://theory.uwinnipeg.ca/physics/circ/node7.html [More results from theory.uwinnipeg.ca] MORE CHALLENGES TO NEWTON'S LAW OF GRAVITATION Home Page, Science Frontiers ONLINE No. 62: Mar-Apr 1989. Issue Contents. Other pages. ... MORE CHALLENGES TO NEWTON'S LAW OF GRAVITATION. ... http://www.science-frontiers.com/sf062/sf062p13.htm [More results from www.science-frontiers.com] The Law of Gravitation next up previous contents Next: Gravitational Field Up: Newton's Law of Gravitation Previous: Newton's Law of Gravitation Contents The Law of Gravitation. ... http://www.physics.nmt.edu/raymond/ph13xbook/node123.html [More results from www.physics.nmt.edu] Newton's Law of Gravitation Mars Academy. Newton's Law of Gravitation. Newton's Law of Universal Gravitation is perhaps ... http://www.marsacademy.com/text/orbits2.htm [More results from www.marsacademy.com] High School Physics TOC - The Law of Gravitation ... Your Location: table of contents > the law of gravitation. ... Linear Motion. Motion in a Plane (2 dimensions). The Law of Gravitation: Gravity: ... http://www.homeworkhelp.com/homeworkhelp/member/text/phys/high/topic05.php [More results from www.homeworkhelp.com] The Universal Law of Gravitation The Universal Law of Gravitation. Gravity is described from the point of view of a universal law. This implies that gravity is a force that should behave in ... http://www.sciencejoywagon.com/physicszone/lesson/02forces/unigrav/gravitat.htm [More results from www.sciencejoywagon.com] Chapter 5 & 8 Sample Problems Home Page of Peggy E. Schweiger Newton's Laws & Universal Law of Gravitation Sample Problems. ... http://members.tripod.com/~PeggySchweiger/sample_problems.htm [More results from members.tripod.com] Newton's Law of Universal Gravitation ... The proportionalities expressed by Newton's universal law of gravitation is represented graphically by the following illustration. Observe how the force of ... http://www.glenbrook.k12.il.us/gbssci/phys/Class/circles/u6l3c.html [More results from www.glenbrook.k12.il.us] xrefer - Newton's law of gravitation ... Newton's law of gravitation, One of the most far-reaching and important physical laws. It states that every particle of matter attracts every other particle of ... http://www.xrefer.com/entry/220748 [More results from www.xrefer.com] Physics 131: Notes -- Newton's Law of Universal Gravitation Prev Up Next Go backward to Kepler's Laws Go up to Top Go forward to Momentum Newton's Law of Universal Gravitation. ... http://www.science.urich.edu/~rubin/pedagogy/131/131notes/Newton.html [More results from www.science.urich.edu] Sci 122: Universal Gravitation Honolulu Community College. ... Newton and Universal Gravitation. Universal Law of Gravitation. All objects in ... http://www.hcc.hawaii.edu/hccinfo/instruct/div5/sci/sci122/newton/Gravity/unilaw.html [More results from www.hcc.hawaii.edu] Newton's Law of Gravitation next up previous Next: Derivation of Kepler's First Up: Kepler's Laws of Motion Previous: Newton's Second law Newton's Law of Gravitation. ... http://look1.apmaths.uwo.ca/apmath282/main/node76.html [More results from look1.apmaths.uwo.ca] FINISHING AN EXAMPLE: NEWTON'S LAW OF GRAVITATION ... FINISHING AN EXAMPLE: NEWTON'S LAW OF GRAVITATION. These two laws, of inertia and of exactly ... http://www.ph.utexas.edu/~gleeson/httb/section1_3_5_5.html [More results from www.ph.utexas.edu] PC1672: 3.1 Universal law of gravitation ... PC1672 Advanced dynamics. 3.1 Universal law of gravitation. Newton's universal law of ... http://theory.ph.man.ac.uk/~mikeb/lecture/pc167/gravity/gravity.html [More results from theory.ph.man.ac.uk] NEWTON S LAW OF GRAVITATION. The Columbia Encyclopedia: Sixth ... ... Reference > Columbia Encyclopedia > Newton s law of gravitation. ... The Columbia Encyclopedia: Sixth Edition. 2000. Newton s law of gravitation ... http://www.bartleby.com/65/x-/X-Newtgrav.html [More results from www.bartleby.com] The Cosmic Journey: Newton's Universal Law of Gravitation The Cosmic Journey. Optional Basic Equation II. Newtons Universal Law of Gravitation. Once ... http://www.astronomica.org/textbook/equations/2_NULoG.html [More results from www.astronomica.org] vik dhillon: phy105 - celestial mechanics - newton's law of ... ... to the mass of the central body. Redefining the constant of proportionality, Newton hence obtained his universal law of gravitation F = Gm 1 m 2 / r 2 , where ... http://www.shef.ac.uk/uni/academic/N-Q/phys/people/vdhillon/teaching/phy105/phy105_gravitation.html [More results from www.shef.ac.uk] Newton's law of gravitation - Britannica.com ... BRITANNICA. Information about this topic in other articles: Newton's law of gravitation major reference gravitation from gravitation Newton's law of gravity ... http://www.britannica.com/bcom/eb/article/index/1/0,8377,57011,00.html [More results from www.britannica.com] ASTR 103: Mathematics of the Law of Gravitation Mathematics of the Law of Gravitation. Latest Modification: October 9, 1996 If m 1 stands ... http://www.physics.gmu.edu/classinfo/astr103/CourseNotes/ECText/Boxes/ch03_bx2.htm [More results from www.physics.gmu.edu] Next 20 matches advanced search - help -------------------------------------------------------------------------------- Other Search Engines Alta Vista - NBCi - Google - Britannica.com - - NorthernLight - Ask Jeeves - More... Yellow Pages - People Search - City Maps - Get Local - Today's Web Events & Chats - More Yahoos -------------------------------------------------------------------------------- Copyright © 2001; Yahoo! Inc. All Rights Reserved.Privacy Policy - Terms of Service - Help - Feedback |